Apparatus for shearing tubular jackets



' Sept. 4, 1962 APPARATUS FOR SHEARING TUBULAR JACKETS Filed Dec. 29,1959 J. P. SIMON 5 Sheets-Sheet 1 INVENTOR.

Jain P 55177012 jfiof zgy p 1962 J. P. SIMON 3,052,142

APPARATUS FOR SHEARING TUBULAR JACKETS Filed Dec. 29, 1959 3Sheets-Sheet 2 INVENTOR.

BY M4. 4M

.5? foxvey p 4, 1962 J. P. SIMON 3,052,142

APPARATUS FOR SHEARING TUBULAR JACKETS Filed Dec. 29, 1959 5Sheets-Sheet 3 United States Patent Ofilice 3,5Z,14Z Patented Sept. 4,1962 3,952,142 APPARATUS FOR SHEAREFG TUBULAR JACKETS John 1. Simon,Glen Ellyn, 111., assignor to the United States of America asrepresented by the United States Atomic Energy Commission Filed Dec. 29,1959, Ser. No. 862,734 3 Claims. (61. 82-54) This invention relates tothe removal of casings from objects. More specifically, it relates to anapparatus for removing a tubular jacket without damage to the contentsof the jacket.

For some time spent fuel elements of nuclear reactors have beenreprocessed for the production of new fuel elements. A big problem insuch reprocessing is the separation and removal of the jacket of thefuel element from the core so that the reprocessing of the core may becarried out. Certain fuel elements to be reprocessed are of the pin orrod type comprising long thin cores of an alloy comprising zirconium,molybdenum, and principally uranium, tubular jackets of stainless steel,and sodium between the jackets and the cores.

Certain devices proposed or tried for removing tubular jackets fromfuel-element cores have tended to damage or break the cores into piecesthat are difiicult to gather up and separate from the jackets. Otherdevices for this purpose cut the fuel-element jackets and thus producesmall scrap jacket particles that are diflicult to separate from thecores. Many of these devices use cutting lubricants or coolants, whichadhere to the cores and complicate the task of reprocessing the cores.

The device of the present invention completely separates thefuel-element jacket and the core from one another as entire unitswithout producing jacket or core fragments and without using lubricantsor coolants.

In the drawings:

FIG. 1 is a diagrammatic view of the entire apparatus to which theshearing device of the present invention is applied;

FIG. 2 is a plan view of the novel shearing device;

FIG. 3 is an elevational view of the shearing device;

FIG. "4 is a sectional view taken on the line 4-4 of FIG. 2 and showinga switch responsive to the passage of a fuel element through theshearing device for releasing the sheared jacket from the device;

FIG. 5 is an end view, with parts broken away and in section, of thenovel shearing device;

FIG. 6 is a sectional view taken on the line 66 of FIG. 5 and showingthe mounting of a tool forming an essential element of the shearingdevice, feed rolls being omitted for the sake of clarity; and

FIG. 7 is a diagrammatic sectional view showing the tool and acooperating roll in relation to a fuel element from the tool and rollshearing the jacket.

As shown in FIG. 1, a plurality of fuel elements 10 are located in ahopper 11 and are released individually by a trigger mechanism 12. Eachfuel element falls into shearing devices 13 and 14 which remove ends 15and 16 of the fuel element 10 and the ends of a spiral spacing wire 17welded to fuel-element ends 15 and 16. The wire 17, which extends alongand about the fuel element 10 to space the same from other fuel elements10 in the reactor, is now loose and becomes separated from the fuelelement as they fall into slotted rests 18 and 19, the slots in therests permitting the wire to fall free through the rests. The rest 18 isfixed, being attached to a fixed member 21 and the rest 19 is shiftable,being carried by a head 21 attached to a rod 22 connected to a piston 23in a pneumatic cylinder 24.

The fuel element 10 is moved axially by the shiftable rest 19 throughthe fixed member into a flared end 25 on a tube 26, through this tube,and out of a contracted end 27 thereon. If the spacing wire 17 hasstayed on the fuel element 10, the wire will be stripped from the fuelelement as it moves through the fixed member 20.

As the fuel element 10 emerges from the contracted end 27 of the tube26, the fuel element moves into a space formed between feeding rolls 28,29, and 30, which engage the fuel element and feed it axially. At thesame time a tool 31 cooperates with the roll 30 in shearing a jacket 32(FIG. 7) on the fuel element 10 into a spiral ribbon 33. A core 34 ofthe fuel element 10, now being stripped of the jacket 32, is fed into achopper 35, which chops the core into short lengths 36.

As shown in FIGS. 2, 3, and 5, the feeding rolls 23, 29, and 31) havetheir axes extending at a small angle, for example, 15, to the axis ofthe fuel element 10 so as to feed the fuel element while rotating it.The rolls 28, 29, and 30 are serrated to grip the fuel element better.The edge of the roll 30 adjacent the tool 31 is sharpened so thatshearing of the jacket 32 into the ribbon 33 is facilitated.

As shown in FIGS. 3, 6, and 7, the tool 31 lies directly adjacent oneface of the roll 30 with a very small clearance between the roll and thetool. As shown in FIG. 7, a tip 37 on the tool 31 lies closer to theaxis of the fuel element 10 by an amount equal to the thickness of thejacket 32 of the fuel element; and an arcuate recess 38 formed on thetool 31 extends from the tip 37 so as to conform generally to the core34 of the fuel element. The tool 31, which is stationary in operation,cuts the leading end of the jacket 32 as the fuel element 11) is fed bythe rolls 28, 29, and 30 to the tool 31 to start the ribbon 33, andthereafter the tool 31 and the feeding roll 31 or more particularly thesharp edge on the adjacent face of the roll 30, cooperate to form theribbon 33 by a shearing action performed along a spiral path on thejacket 32. In this way, the jacket is removed from the core 34 of thefuel element 10.

The leading end of the fuel element 10 arriving at the rollers 28, 29,and 30 and tool 31 has no end plug or closure, since the shearing device13 has severed the end 15 just beyond the end of the core 34-.

As shown in FIG. 4, a roller follower 39 rides the fuel element 10 justbeyond the contracted end 27 of the tube 25. When the rear end of thefuel element 10 moves beyond the follower 39, it drops from thefull-line position to the dotted-line position of FIG. 4 and therebycauses the tool 31 to drop from the full-line position of FIG. 7 to thebroken-line position in which it is spaced from the fuel element 10.Thus the shearing of the fuel-element jacket 32 is stopped and the rearend of the fuel element 10, comprising an end plug (not shown) and theend of the jacket 32 attached to the end plug and still connected to theribbon 33, is released from the feeding rolls 28, 29, and 30 by beingfed out of them. By the time the tool 31 is shifted away from the fuelelement 10, the shearing of the jacket 32 by the tool 31 and the roll 30will have extended to about the end of the fuel core 34, so that noportion of the core is carried along with the ribbon 33.

As shown in P16. 5, the tool 31 is attached by set screw 39a to a holder40 which is slidably carried in a bed 41 and retained therein by a coverplate 41a secured to the bed by screws 41b. The bed 41 is attached to amounting block 42. A wedge 43 is attached to the holder 4-0 and isyieldingly urged away from the bed 41 by coil springs 44 lodged inrecesses in the block and wedge so that the tendency is to move the tool31 away from the fuel element 10. The wedge 43 is engaged by a wedge 45connected by a rod 4-6 to a piston 45a slidable in a pneumatic cylinder47. The cylinder 47 is secured to the mounting block 42, which carries asupport 48 along which the wedge slides.

When the fuel element 10 has been fed by the rolls 28, 29, and 30 beyondthe follower 39 so that it drops to the broken-line position of FIG. 4,a switch 48a is actuated to open an electric circuit causing a valve(not shown) to stop the supplying of gas under pressure to the side ofthe piston 46a away from the rod 46. Thus the wedge 45 is shifted to theright as viewed in FIG. 5 into contact with a shoulder stop 48b on thecylinder 47, by a spring 49 in the cylinder 47 acting against the piston464:, so that the wedge 43 and tool 31 can move downward, whereby thefuel element is released. When a new fuel element 10 is moved by theshiftable rest 19 through the tube 26 far enough to lift the follower 39to the full-line position of FIG. 4, the electric circuit controllingthe supply of gas under pressure against the piston 46a is closed, andso the piston 46a and wedge 45 move leftward as viewed in FIG. 5, andthe wedge 43 and the tool 31 are moved upward so that tool 31 is againin position to work with the feeding roll 30 in shearing the ribbon 33from the fuel-element jacket 32.

The dropping of the follower 39 as the first fuel element moves beyondthe follower will have caused the hopper 11 to release the new fuelelement, to actuate the shearing devices 13 and 14 upon arrival of thenew fuel element thereat, and to cause the movement of the shiftablerest 19 upon receiving the new fuel element, but the details forcarrying out these operations are not shown, since they do not form, perse, a part of the present invention, which comprises, instead, thearrangement of feeding rolls 28, 29, and 30 and the tool 31.

As shown in FIGS. 2, 3, 5, and 6, the rolls 29 and 30 are attached toshafts 50 and 51 journaled in spaced mounting blocks 42 and 52, attachedto a plate 53, in turn attached to a base 54. The roll 28 is attached toa shaft 55 journaled in a part 56, which is pivotally connected by a pin57 and ears 58 to the mounting blocks 42 and 52 and restrained by a coilspring 59 and a screw 60. The spring 59 is retained between the part 56and the head of the screw 60, which freely extends through the spring 59and the part 56 into a threaded connection with the mounting block 42.The roll 28 is movable away from the rolls 29 and 30 against the actionof the spring 59, so that the rolls 28, 29, and 30 accommodate fuelelements 10 of different diameter as well as bent fuel elements. Theroll shafts 50, 51, and 55 are, of course, not parallel to one another,but are connected through universal joints to parallel drive shafts 61,62, and 63, respectively, which are journaled in an upright 64 and carrysprockets 65 meshing with a sprocket chain 66 connected to a drivingmotor (not shown).

The tube 26, through which the fuel element 10 moves on its way to thefeeding rolls 28, 29, and 30 and the tool 31, is mounted in the block 52and the upright 64. The block 42, which is only a short distance fromthe contracted end 27 of the tube 26, has a tapered opening 67 which isaligned with the tube 26 and has its small end just a little larger thanthe fuel element 10 so as to guide it between the feeding rolls 28, 29,and 30.

The rolls 28, 29, and 30 and the tool 31 may be formed of oil-quenchedtool steel. The fuel-element jacket 32 may be a #304 hard drawnstainless steel tube having a wall thickness of 0.009 and an outerdiameter of .174".

The fuel-element core 34 may be of an alloy composed, beforeirradiation, of 92 w/o highly enriched uranium, 0.10 w/o Zirconium, 3.4w/o molybdenum, and some other elements, and have a length of 14" and adiameter of 0.144". There may be a thermal-bond layer of sodium betweenthe core 34 and the jacket 32. In the reactor the jacket and core mayhave become mechanically bonded or welded to one another at certainregions. The fuel element 10 processed by the rolls 28, 29, and 30 andtool 31 has been described as sheared of its ends 15 and 16 so that ithas no end plug or closure at the leading end of the core 34, but doeshave an end plug or closure at the trailing end. It will be understoodthat the rolls 28, 29, and 30 and tool 31 might also shear the jacketfrom a fuel element having an end plug at neither end. Moreover, therolls 28, 29, and 30 and tool 31 are also capable of shearing a tubeinto a ribbon, even though there is no core in the tube. In any event,it is important that the tool 31 be withdrawn to the broken-lineposition of FIG. 7 while a portion of the rear end of the jacket 32 (ortube) remains in the rolls 28, 29, and 30, for if the rear end of thejacket is fed out of the rolls while the tool 31 is in shearingposition, the rear end of the jacket may become caught on the tool.Furthermore, cutting the region of the tube or jacket 32 where the endplug is located might dislodge the end plug and cause it in some way tobecome mixed with the short lengths 36 of the core 34.

The intention is to limit the claims only within the scope of theappended claims.

What is claimed is:

l. A device for removing a tubular jacket from a core lying therein,said device comprising a plurality of feeding rolls surrounding thetubular jacket so as to feed the same axially, and a tool lying directlyadjacent and cooperating with an end face of one of the feeding rolls soas to shear the tubular jacket into a spiral strip.

2. A device for cutting a tube into a spiral strip, comprising threerolls spaced about the tube for feeding the same axially, the axes ofthe rolls being at a small angle to the aXis of the tube, and astationary tool lying directly adjacent and cooperating with an end faceof one of the rolls for shearing the tube against the said one roll.

3. A device for removing a tubular jacket from the core of anuclear-fuel element, said device comprising three serrated feedingrolls spaced about the jacket for feeding the jacket and elementaxially, the axes of the rolls being at a small angle to the axis of thejacket, one roll having a sharp edge at one end, and a stationary toollying directly adjacent the said one end of the one roll and having atip somewhat closer to the axis of the jacket than the sharp edge of theone roll and an arcuate portion extending from the tip and generallyconforming to the core of the fuel element, whereby said tool cooperates with the sharp edge of the one roll to shear the tubular jacketinto a strip.

References Cited in the file of this patent UNITED STATES PATENTS1,643,157 Gardner Sept. 20, 1927 1,756,171 Boomer Apr. 29, 19302,323,700 Bailey July 6, 1943

